U.S. patent application number 14/478261 was filed with the patent office on 2015-07-02 for wireless charging circuit for power bank and power bank thereof.
The applicant listed for this patent is Generalplus Technology Inc.. Invention is credited to Down Xu CHUANG.
Application Number | 20150188355 14/478261 |
Document ID | / |
Family ID | 53482988 |
Filed Date | 2015-07-02 |
United States Patent
Application |
20150188355 |
Kind Code |
A1 |
CHUANG; Down Xu |
July 2, 2015 |
WIRELESS CHARGING CIRCUIT FOR POWER BANK AND POWER BANK THEREOF
Abstract
A wireless charging circuit for power bank and a power bank
thereof are provided in the present invention. The wireless
charging circuit includes a boost DC to DC converter, a
unidirectional conductive element and a wireless power converter.
The input terminal of the boost DC to DC converter is coupled to
the battery to receive the battery voltage. The output terminal of
the boost DC to DC converter outputs a converted DC voltage. The
first terminal of the unidirectional conductive element is coupled
to the battery to receive the battery voltage, wherein the
direction of the current flow is from the first terminal of the
unidirectional conductive element to the second terminal of the
unidirectional conductive element. The input terminal of the
wireless power converter is coupled to the second terminal of the
unidirectional conductive element. When the wireless charging
circuit performs the detection for the wireless power receiver, the
wireless power converter disables the boost DC to DC converter.
Inventors: |
CHUANG; Down Xu; (Zhunan
Township, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Generalplus Technology Inc. |
Hsinchu City |
|
TW |
|
|
Family ID: |
53482988 |
Appl. No.: |
14/478261 |
Filed: |
September 5, 2014 |
Current U.S.
Class: |
320/108 |
Current CPC
Class: |
H02J 50/12 20160201;
H02J 50/60 20160201; H02J 2207/20 20200101; H02J 7/00 20130101;
H02J 5/005 20130101 |
International
Class: |
H02J 7/02 20060101
H02J007/02; H02J 7/00 20060101 H02J007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 27, 2013 |
TW |
102148710 |
Claims
1. A wireless charging circuit, adapted for a power bank, wherein
the power bank comprises a battery, wherein the wireless charging
circuit comprises: a boost DC to DC converter, comprising an input
terminal and an output terminal, wherein the input terminal of the
boost DC to DC converter is coupled to the battery to receive a
battery voltage, wherein the output terminal of the boost DC to DC
converter is for outputting a converted DC voltage; a
unidirectional conductive element, comprising a first terminal and
a second terminal, wherein the first terminal of the unidirectional
conductive element is coupled to the battery to receive the battery
voltage, wherein a current direction is from the first terminal of
the unidirectional conductive element to the second terminal of the
unidirectional conductive element; and a wireless power converter,
coupled to the second terminal of the unidirectional conductive
element and the output terminal of the boost DC to DC converter,
wherein the wireless power converter disables the boost DC to DC
converter when the wireless charging circuit determines whether an
external object is disposed on the wireless power converter or not,
wherein the wireless power converter enables the boost DC to DC
converter when the wireless charging circuit determines that an
external object is disposed on the wireless power converter.
2. The wireless charging circuit according to claim 1, wherein the
boost DC to DC converter comprises an enable terminal, and the
wireless power converter comprises: a low voltage pulse width
modulation (PWM) circuit, comprising an input terminal and an
output terminal, wherein the input terminal of the low voltage PWM
circuit is coupled to the second terminal of the unidirectional
conductive element, and the output terminal of the low voltage PWM
circuit outputs a PWM detecting signal; a resonant circuit,
comprising a first input terminal, wherein the first input terminal
is coupled to the output terminal of the low voltage PWM circuit;
and a control circuit, coupled to the enable terminal of the boost
DC to DC converter; wherein, the control circuit controls the boost
DC to DC converter to disable the boost DC to DC converter when the
wireless charging circuit determines whether an external object is
disposed on the wireless power converter or not.
3. The wireless charging circuit according to claim 2, wherein the
resonant circuit further comprises a second input terminal, and the
resonant circuit comprises: a resonant coil, comprising a first
terminal and a second terminal, wherein the first terminal of the
resonant coil is coupled to the first input terminal of the
resonant circuit; and a resonant capacitor, comprising a first
terminal and a second terminal, wherein the first terminal of the
resonant capacitor is coupled to the second terminal of the
resonant coil, and the second terminal of the resonant capacitor is
coupled to the second input terminal of the resonant circuit.
4. The wireless charging circuit according to claim 2, wherein the
resonant circuit further comprises a second input terminal, and the
resonant circuit comprises: a resonant capacitor, comprising a
first terminal and a second terminal, wherein the first terminal of
the resonant capacitor is coupled to the first input terminal of
the resonant circuit; and a resonant coil, comprising a first
terminal and a second terminal, wherein the first terminal of the
resonant coil is coupled to the second terminal of the resonant
capacitor, and the second terminal of the resonant coil is coupled
to the second input terminal of the resonant circuit.
5. The wireless charging circuit according to claim 2, wherein the
low power PWM circuit comprises: a first upper switch, comprising a
first terminal, a second terminal and a control terminal, wherein
the control terminal of the first upper switch is coupled to the
control circuit, and the first terminal of the first upper switch
is coupled to the second terminal of the unidirectional conductive
element; and a first lower switch, comprising a first terminal, a
second terminal and a control terminal, wherein the control
terminal of the first lower switch is coupled to the control
circuit, the first terminal of the first lower switch is coupled to
the second terminal of the first upper switch and the first input
terminal of the resonant circuit, and the second terminal of the
first lower switch is coupled to a common voltage.
6. The wireless charging circuit according to claim 2, further
comprising: a high voltage pulse width modulation (PWM) circuit,
coupled to the output terminal of the boost DC to DC converter for
outputting a driving PWM signal to the resonant circuit; and a
driving circuit, coupled to the high voltage pulse width modulation
circuit, the boost DC to DC converter and the control circuit,
wherein the control circuit enables the boost DC to DC converter
and the control circuit enables the driving circuit to drive the
high voltage PWM circuit when the wireless charging circuit
determines that an external object is disposed on the wireless
power converter.
7. The wireless charging circuit according to claim 6, wherein the
high voltage PWM circuit comprises: a second upper switch,
comprising a first terminal, a second terminal and a control
terminal, wherein the control terminal of the second upper switch
is coupled to the driving circuit, and the first terminal of the
second upper switch is coupled to the output terminal of the boost
DC to DC converter; and a second lower switch, comprising a first
terminal, a second terminal and a control terminal, wherein the
control terminal of the second lower switch is coupled to the
driving circuit, the first terminal of the second lower switch is
coupled to the second terminal of the second upper switch and the
first input terminal of the resonant circuit, and the second
terminal of the second lower switch is coupled to a common
voltage.
8. The wireless charging circuit according to claim 7, wherein the
resonant circuit further comprises a second input terminal, and
high voltage PWM circuit further comprises: a third upper switch,
comprising a first terminal, a second terminal and a control
terminal, wherein the control terminal of the third upper switch is
coupled to the driving circuit, and the first terminal of the third
upper switch is coupled to the output terminal of the boost DC to
DC converter; and a third lower switch, comprising a first
terminal, a second terminal and a control terminal, wherein the
control terminal of the third lower switch is coupled to the
driving circuit, the first terminal of the third lower switch is
coupled to the second terminal of the third upper switch and the
second input terminal of the resonant circuit, and the second
terminal of the third lower switch is coupled to the common
voltage.
9. The wireless charging circuit according to claim 8, further
comprising: a detection switch, comprising a first terminal, a
second terminal and a control terminal, wherein the control
terminal of the detection switch is coupled to the control circuit,
the first terminal of the detection switch is coupled to the second
input terminal of the resonant circuit, and the second terminal of
the detection switch is coupled to the common voltage, wherein the
control circuit controls the detection switch to connect the first
terminal of the detection switch with the second terminal of the
detection switch when the wireless charging circuit determines
whether an external object is disposed on the wireless power
converter or not.
10. A mobile power bank, comprising: a battery; and a wireless
charging circuit, comprising: a boost DC to DC converter,
comprising an input terminal and an output terminal, wherein the
input terminal of the boost DC to DC converter is coupled to the
battery to receive a battery voltage, wherein the output terminal
of the boost DC to DC converter is for outputting a converted DC
voltage; a unidirectional conductive element, comprising a first
terminal and a second terminal, wherein the first terminal of the
unidirectional conductive element is coupled to the battery to
receive the battery voltage, wherein a current direction is from
the first terminal of the unidirectional conductive element to the
second terminal of the unidirectional conductive element; and a
wireless power converter, coupled to the second terminal of the
unidirectional conductive element and the output terminal of the
boost DC to DC converter, wherein the wireless power converter
disables the boost DC to DC converter when the wireless charging
circuit determines whether an external object is disposed on the
wireless power converter or not, wherein the wireless power
converter enables the boost DC to DC converter when the wireless
charging circuit determines that an external object is disposed on
the wireless power converter.
11. The mobile power bank according to claim 10, wherein the boost
DC to DC converter comprises an enable terminal, and the wireless
power converter comprises: a low voltage pulse width modulation
(PWM) circuit, comprising an input terminal and an output terminal,
wherein the input terminal of the low voltage PWM circuit is
coupled to the second terminal of the unidirectional conductive
element, and the output terminal of the low voltage PWM circuit
outputs a PWM detecting signal; a resonant circuit, comprising a
first input terminal, wherein the first input terminal is coupled
to the output terminal of the low voltage PWM circuit; and a
control circuit, coupled to the enable terminal of the boost DC to
DC converter; wherein, the control circuit controls the boost DC to
DC converter to disable the boost DC to DC converter when the
wireless charging circuit determines whether an external object is
disposed on the wireless power converter or not.
12. The mobile power bank according to claim 11, wherein the
resonant circuit further comprises a second input terminal, and the
resonant circuit comprises: a resonant coil, comprising a first
terminal and a second terminal, wherein the first terminal of the
resonant coil is coupled to the first input terminal of the
resonant circuit; and a resonant capacitor, comprising a first
terminal and a second terminal, wherein the first terminal of the
resonant capacitor is coupled to the second terminal of the
resonant coil, and the second terminal of the resonant capacitor is
coupled to the second input terminal of the resonant circuit.
13. The mobile power bank according to claim 11, wherein the
resonant circuit further comprises a second input terminal, and the
resonant circuit comprises: a resonant capacitor, comprising a
first terminal and a second terminal, wherein the first terminal of
the resonant capacitor is coupled to the first input terminal of
the resonant circuit; and a resonant coil, comprising a first
terminal and a second terminal, wherein the first terminal of the
resonant coil is coupled to the second terminal of the resonant
capacitor, and the second terminal of the resonant coil is coupled
to the second input terminal of the resonant circuit.
14. The mobile power bank according to claim 11, wherein the low
power PWM circuit comprises: a first upper switch, comprising a
first terminal, a second terminal and a control terminal, wherein
the control terminal of the first upper switch is coupled to the
control circuit, and the first terminal of the first upper switch
is coupled to the second terminal of the unidirectional conductive
element; and a first lower switch, comprising a first terminal, a
second terminal and a control terminal, wherein the control
terminal of the first lower switch is coupled to the control
circuit, the first terminal of the first lower switch is coupled to
the second terminal of the first upper switch and the first input
terminal of the resonant circuit, and the second terminal of the
first lower switch is coupled to a common voltage.
15. The mobile power bank according to claim 11, further
comprising: a high voltage pulse width modulation (PWM) circuit,
coupled to the output terminal of the boost DC to DC converter for
outputting a driving PWM signal to the resonant circuit; and a
driving circuit, coupled to the high voltage pulse width modulation
circuit, the boost DC to DC converter and the control circuit,
wherein the control circuit enables the boost DC to DC converter
and the control circuit enables the driving circuit to drive the
high voltage PWM circuit when the wireless charging circuit
determines that an external object is disposed on the wireless
power converter.
16. The mobile power bank according to claim 15, wherein the high
voltage PWM circuit comprises: a second upper switch, comprising a
first terminal, a second terminal and a control terminal, wherein
the control terminal of the second upper switch is coupled to the
driving circuit, and the first terminal of the second upper switch
is coupled to the output terminal of the boost DC to DC converter;
and a second lower switch, comprising a first terminal, a second
terminal and a control terminal, wherein the control terminal of
the second lower switch is coupled to the driving circuit, the
first terminal of the second lower switch is coupled to the second
terminal of the second upper switch and the first input terminal of
the resonant circuit, and the second terminal of the second lower
switch is coupled to a common voltage.
17. The mobile power bank according to claim 16, wherein the
resonant circuit further comprises a second input terminal, and
high voltage PWM circuit further comprises: a third upper switch,
comprising a first terminal, a second terminal and a control
terminal, wherein the control terminal of the third upper switch is
coupled to the driving circuit, and the first terminal of the third
upper switch is coupled to the output terminal of the boost DC to
DC converter; and a third lower switch, comprising a first
terminal, a second terminal and a control terminal, wherein the
control terminal of the third lower switch is coupled to the
driving circuit, the first terminal of the third lower switch is
coupled to the second terminal of the third upper switch and the
second input terminal of the resonant circuit, and the second
terminal of the third lower switch is coupled to the common
voltage.
18. The mobile power bank according to claim 17, further
comprising: a detection switch, comprising a first terminal, a
second terminal and a control terminal, wherein the control
terminal of the detection switch is coupled to the control circuit,
the first terminal of the detection switch is coupled to the second
input terminal of the resonant circuit, and the second terminal of
the detection switch is coupled to the common voltage, wherein the
control circuit controls the detection switch to connect the first
terminal of the detection switch with the second terminal of the
detection switch when the wireless charging circuit determines
whether an external object is disposed on the wireless power
converter or not.
19. A wireless charging circuit, adapted for a power bank, wherein
the power bank comprises a battery, wherein the wireless charging
circuit comprises: a boost DC to DC converter, comprising an input
terminal and an output terminal, wherein the input terminal of the
boost DC to DC converter is coupled to the battery to receive a
battery voltage, wherein the output terminal of the boost DC to DC
converter is for outputting a converted DC voltage; a control
circuit, coupled to the battery to receive the battery voltage; a
low voltage pulse width modulation (PWM) circuit, coupled to the
control circuit and the battery to receive the battery voltage, for
outputting a low voltage PWM signal according to the control of the
control circuit; a wireless power converter, comprising; a high
voltage PWM circuit, coupled to the control circuit and the output
terminal of the boost DC to DC converter, for outputting a high
voltage PWM signal according to the control of the control circuit;
and a resonant circuit, comprising a first input terminal, wherein
the first input terminal of the resonant circuit is coupled to the
low voltage PWM circuit and a high voltage PWM circuit; wherein the
wireless power converter disables the boost DC to DC converter and
the high voltage PWM circuit and the wireless power converter
controls the low voltage PWM circuit to output the low voltage PWM
signal to the resonant circuit when the wireless charging circuit
determines whether an external object is disposed on the wireless
power converter or not, wherein the wireless power converter
enables the boost DC to DC converter and the high voltage PWM
circuit and the wireless power converter disables the low voltage
PWM circuit when the wireless charging circuit determines that an
external object is disposed on the wireless power converter.
20. The wireless charging circuit according to claim 19, wherein
the resonant circuit further comprises a second input terminal, and
the resonant circuit comprises: a resonant coil, comprising a first
terminal and a second terminal, wherein the first terminal of the
resonant coil is coupled to the first input terminal of the
resonant circuit; and a resonant capacitor, comprising a first
terminal and a second terminal, wherein the first terminal of the
resonant capacitor is coupled to the second terminal of the
resonant coil, and the second terminal of the resonant capacitor is
coupled to the second input terminal of the resonant circuit.
21. The wireless charging circuit according to claim 19, wherein
the resonant circuit further comprises a second input terminal, and
the resonant circuit comprises: a resonant capacitor, comprising a
first terminal and a second terminal, wherein the first terminal of
the resonant capacitor is coupled to the first input terminal of
the resonant circuit; and a resonant coil, comprising a first
terminal and a second terminal, wherein the first terminal of the
resonant coil is coupled to the second terminal of the resonant
capacitor, and the second terminal of the resonant coil is coupled
to the second input terminal of the resonant circuit.
22. The wireless charging circuit according to claim 19, wherein
the low power PWM circuit comprises: a first upper switch,
comprising a first terminal, a second terminal and a control
terminal, wherein the control terminal of the first upper switch is
coupled to the control circuit, and the first terminal of the first
upper switch is coupled to the battery to receive the battery
voltage; and a first lower switch, comprising a first terminal, a
second terminal and a control terminal, wherein the control
terminal of the first lower switch is coupled to the control
circuit, the first terminal of the first lower switch is coupled to
the second terminal of the first upper switch and the first input
terminal of the resonant circuit, and the second terminal of the
first lower switch is coupled to a common voltage.
23. The wireless charging circuit according to claim 19, further
comprising: a driving circuit, coupled to the high voltage pulse
width modulation circuit, the boost DC to DC converter and the
control circuit, wherein the control circuit enables the boost DC
to DC converter and the control circuit enables the driving circuit
to drive the high voltage PWM circuit when the wireless charging
circuit determines that an external object is disposed on the
wireless power converter.
24. The wireless charging circuit according to claim 23, wherein
the high voltage PWM circuit comprises: a second upper switch,
comprising a first terminal, a second terminal and a control
terminal, wherein the control terminal of the second upper switch
is coupled to the driving circuit, and the first terminal of the
second upper switch is coupled to the output terminal of the boost
DC to DC converter; and a second lower switch, comprising a first
terminal, a second terminal and a control terminal, wherein the
control terminal of the second lower switch is coupled to the
driving circuit, the first terminal of the second lower switch is
coupled to the second terminal of the second upper switch and the
first input terminal of the resonant circuit, and the second
terminal of the second lower switch is coupled to a common
voltage.
25. The wireless charging circuit according to claim 24, wherein
the resonant circuit further comprises a second input terminal, and
high voltage PWM circuit further comprises: a third upper switch,
comprising a first terminal, a second terminal and a control
terminal, wherein the control terminal of the third upper switch is
coupled to the driving circuit, and the first terminal of the third
upper switch is coupled to the output terminal of the boost DC to
DC converter; and a third lower switch, comprising a first
terminal, a second terminal and a control terminal, wherein the
control terminal of the third lower switch is coupled to the
driving circuit, the first terminal of the third lower switch is
coupled to the second terminal of the third upper switch and the
second input terminal of the resonant circuit, and the second
terminal of the third lower switch is coupled to the common
voltage.
26. The wireless charging circuit according to claim 25, further
comprising: a detection switch, comprising a first terminal, a
second terminal and a control terminal, wherein the control
terminal of the detection switch is coupled to the control circuit,
the first terminal of the detection switch is coupled to the second
input terminal of the resonant circuit, and the second terminal of
the detection switch is coupled to the common voltage, wherein the
control circuit controls the detection switch to connect the first
terminal of the detection switch with the second terminal of the
detection switch when the wireless charging circuit determines
whether an external object is disposed on the wireless power
converter or not.
27. A mobile power bank, comprising: a battery; and a wireless
charging circuit, comprising: a boost DC to DC converter,
comprising an input terminal and an output terminal, wherein the
input terminal of the boost DC to DC converter is coupled to the
battery to receive a battery voltage, wherein the output terminal
of the boost DC to DC converter is for outputting a converted DC
voltage; a control circuit, coupled to the battery to receive the
battery voltage; a low voltage pulse width modulation (PWM)
circuit, coupled to the control circuit and the battery to receive
the battery voltage, for outputting a low voltage PWM signal
according to the control of the control circuit; a wireless power
converter, comprising; a high voltage PWM circuit, coupled to the
control circuit and the output terminal of the boost DC to DC
converter, for outputting a high voltage PWM signal according to
the control of the control circuit; and a resonant circuit,
comprising a first input terminal, wherein the first input terminal
of the resonant circuit is coupled to the low voltage PWM circuit
and a high voltage PWM circuit; wherein the wireless power
converter disables the boost DC to DC converter and the high
voltage PWM circuit and the wireless power converter controls the
low voltage PWM circuit to output the low voltage PWM signal to the
resonant circuit when the wireless charging circuit determines
whether an external object is disposed on the wireless power
converter or not, wherein the wireless power converter enables the
boost DC to DC converter and the high voltage PWM circuit and the
wireless power converter disables the low voltage PWM circuit when
the wireless charging circuit determines that an external object is
disposed on the wireless power converter.
28. The mobile power bank according to claim 27, wherein the
resonant circuit further comprises a second input terminal, and the
resonant circuit comprises: a resonant coil, comprising a first
terminal and a second terminal, wherein the first terminal of the
resonant coil is coupled to the first input terminal of the
resonant circuit; and a resonant capacitor, comprising a first
terminal and a second terminal, wherein the first terminal of the
resonant capacitor is coupled to the second terminal of the
resonant coil, and the second terminal of the resonant capacitor is
coupled to the second input terminal of the resonant circuit.
29. The mobile power bank according to claim 27, wherein the
resonant circuit further comprises a second input terminal, and the
resonant circuit comprises: a resonant capacitor, comprising a
first terminal and a second terminal, wherein the first terminal of
the resonant capacitor is coupled to the first input terminal of
the resonant circuit; and a resonant coil, comprising a first
terminal and a second terminal, wherein the first terminal of the
resonant coil is coupled to the second terminal of the resonant
capacitor, and the second terminal of the resonant coil is coupled
to the second input terminal of the resonant circuit.
30. The mobile power bank according to claim 27, wherein the low
power PWM circuit comprises: a first upper switch, comprising a
first terminal, a second terminal and a control terminal, wherein
the control terminal of the first upper switch is coupled to the
control circuit, and the first terminal of the first upper switch
is coupled to the battery to receive the battery voltage; and a
first lower switch, comprising a first terminal, a second terminal
and a control terminal, wherein the control terminal of the first
lower switch is coupled to the control circuit, the first terminal
of the first lower switch is coupled to the second terminal of the
first upper switch and the first input terminal of the resonant
circuit, and the second terminal of the first lower switch is
coupled to a common voltage.
31. The mobile power bank according to claim 27, further
comprising: a driving circuit, coupled to the high voltage pulse
width modulation circuit, the boost DC to DC converter and the
control circuit, wherein the control circuit enables the boost DC
to DC converter and the control circuit enables the driving circuit
to drive the high voltage PWM circuit when the wireless charging
circuit determines that an external object is disposed on the
wireless power converter.
32. The mobile power bank according to claim 31, wherein the high
voltage PWM circuit comprises: a second upper switch, comprising a
first terminal, a second terminal and a control terminal, wherein
the control terminal of the second upper switch is coupled to the
driving circuit, and the first terminal of the second upper switch
is coupled to the output terminal of the boost DC to DC converter;
and a second lower switch, comprising a first terminal, a second
terminal and a control terminal, wherein the control terminal of
the second lower switch is coupled to the driving circuit, the
first terminal of the second lower switch is coupled to the second
terminal of the second upper switch and the first input terminal of
the resonant circuit, and the second terminal of the second lower
switch is coupled to a common voltage.
33. The mobile power bank according to claim 32, wherein the
resonant circuit further comprises a second input terminal, and
high voltage PWM circuit further comprises: a third upper switch,
comprising a first terminal, a second terminal and a control
terminal, wherein the control terminal of the third upper switch is
coupled to the driving circuit, and the first terminal of the third
upper switch is coupled to the output terminal of the boost DC to
DC converter; and a third lower switch, comprising a first
terminal, a second terminal and a control terminal, wherein the
control terminal of the third lower switch is coupled to the
driving circuit, the first terminal of the third lower switch is
coupled to the second terminal of the third upper switch and the
second input terminal of the resonant circuit, and the second
terminal of the third lower switch is coupled to the common
voltage.
34. The mobile power bank according to claim 33, further
comprising: a detection switch, comprising a first terminal, a
second terminal and a control terminal, wherein the control
terminal of the detection switch is coupled to the control circuit,
the first terminal of the detection switch is coupled to the second
input terminal of the resonant circuit, and the second terminal of
the detection switch is coupled to the common voltage, wherein the
control circuit controls the detection switch to connect the first
terminal of the detection switch with the second terminal of the
detection switch when the wireless charging circuit determines
whether an external object is disposed on the wireless power
converter or not.
Description
[0001] This application claims priority of No. 102148710 filed in
Taiwan R.O.C. on Dec. 27, 2013 under 35 USC 119, the entire content
of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of Invention
[0003] The present invention relates to the wireless power
transmission and feedback technology, and more particularly to a
wireless charging circuit adapted for a mobile power bank and a
mobile power bank using the same.
[0004] 2. Related Art
[0005] Wireless charging technology is a technology for charging
device by electromagnetic field without any wire. Wireless charging
technology is evolved from the wireless power transmission
technology to use the magnetic resonant to transmit the electrical
charge from charger to device to resonate coil and capacitor
between the charge and device to achieve a high efficient power
transmission. The wireless charger is more safer, no exposed
connections, no leakage current. Thus, a lot of problems in wired
charger is prevented.
[0006] Due to the development of the wireless charging technology,
Wireless Power Consortium is established because of the situation.
One of accomplishments of Wireless Power Consortium is to promote
Qi standard. With the standardization, wireless charging technology
is more widely adopted.
[0007] Additionally, since the mobile power bank is widely used,
many manufacturers want to launch a product combining the wireless
charging circuit and mobile power bank. The mobile power bank
adopts the battery to be the main power source. Generally, the
battery supplies 3.7V. However, the wireless charging circuit needs
5V input voltage to operate. Thus, between the wireless charging
circuit and the battery, it must design a DC to DC converter. FIG.
1 illustrates a circuit diagram depicting a wireless charging
circuit according to a conventional art. Referring to FIG. 1, in
this circuit diagram, a boost DC to DC converter 103 is implemented
between the battery 101 and the wireless charging circuit 102. When
the wireless charging circuit 102 detects whether a wireless power
receiver is disposed on the wireless charging circuit 102 or not,
the boost DC to DC converter 103 must be enabled so that the
detection can be performed. Thus, if an external object is disposed
on the wireless charging circuit, the boost DC to DC converter 103
would be enabled. It causes the conversion loss and then the usage
time of the power bank is decreased.
SUMMARY OF THE INVENTION
[0008] It is therefore an objective of the present invention to
provide a wireless charging circuit adapted for a mobile power bank
and a mobile power bank using the same such that the power
consumption from the detection of the external object can be
reduced and the life time of the power bank can be extended.
[0009] To achieve the above-identified or other objectives, the
present invention provides wireless charging circuit, which is
adapted for a power bank, wherein the power bank includes a
battery. The wireless charging circuit includes a boost DC to DC
converter, a unidirectional conductive element, and a wireless
power converter. The boost DC to DC converter includes an input
terminal and an output terminal, wherein the input terminal of the
boost DC to DC converter is coupled to the battery to receive a
battery voltage, wherein the output terminal of the boost DC to DC
converter is for outputting a converted DC voltage. The
unidirectional conductive element includes a first terminal and a
second terminal, wherein the first terminal of the unidirectional
conductive element is coupled to the battery to receive the battery
voltage, wherein a current direction is from the first terminal of
the unidirectional conductive element to the second terminal of the
unidirectional conductive element. The wireless power converter is
coupled to the second terminal of the unidirectional conductive
element and the output terminal of the boost DC to DC converter.
When the wireless charging circuit determines whether an external
object is disposed on the wireless power converter or not, the
wireless power converter disables the boost DC to DC converter.
When the wireless charging circuit determines that an external
object is disposed on the wireless power converter, the wireless
power converter enables the boost DC to DC converter.
[0010] In the wireless charging circuit according to the preferred
embodiment of the present invention, the wireless power converter
includes a low voltage pulse width modulation (PWM) circuit, a
resonant circuit and a control circuit. The low voltage PWM circuit
includes an input terminal and an output terminal, wherein the
input terminal of the low voltage PWM circuit is coupled to the
second terminal of the unidirectional conductive element, and the
output terminal of the low voltage PWM circuit outputs a PWM
detecting signal. The resonant circuit includes a first input
terminal, wherein the first input terminal is coupled to the output
terminal of the low voltage PWM circuit. The control circuit is
coupled to the enable terminal of the boost DC to DC converter.
When the wireless charging circuit determines whether an external
object is disposed on the wireless power converter or not, the
control circuit controls the boost DC to DC converter to disable
the boost DC to DC converter. Furthermore, in a preferred
embodiment, the low power PWM circuit includes a first upper switch
and a first lower switch, wherein the first upper switch and the
first lower switch is composed of a half bridge converter
controlled by the battery voltage.
[0011] In the wireless charging circuit according to the preferred
embodiment of the present invention, the wireless power converter
further includes a high voltage pulse width modulation (PWM)
circuit and a driving circuit. The high voltage PWM circuit is
coupled to the output terminal of the boost DC to DC converter for
outputting a driving PWM signal to the resonant circuit. The
driving circuit is coupled to the high voltage pulse width
modulation circuit, the boost DC to DC converter and the control
circuit. When the wireless charging circuit determines that an
external object is disposed on the wireless power converter, the
control circuit enables the boost DC to DC converter and the
control circuit enables the driving circuit to drive the high
voltage PWM circuit.
[0012] In the wireless charging circuit according to the preferred
embodiment of the present invention, the high voltage PWM circuit
includes a second upper switch and a second lower switch. The
control terminal of the second upper switch is coupled to the
driving circuit, and the first terminal of the second upper switch
is coupled to the output terminal of the boost DC to DC converter.
The control terminal of the second lower switch is coupled to the
driving circuit, the first terminal of the second lower switch is
coupled to the second terminal of the second upper switch and the
first input terminal of the resonant circuit, and the second
terminal of the second lower switch is coupled to a common voltage.
In another preferred embodiment, the high voltage PWM circuit is a
full bridge converter, and the resonant circuit further includes a
second input terminal. Thus, the high voltage PWM circuit further
includes a third upper switch and a third lower switch. The control
terminal of the third upper switch is coupled to the driving
circuit, and the first terminal of the third upper switch is
coupled to the output terminal of the boost DC to DC converter. The
control terminal of the third lower switch is coupled to the
driving circuit, the first terminal of the third lower switch is
coupled to the second terminal of the third upper switch and the
second input terminal of the resonant circuit, and the second
terminal of the third lower switch is coupled to the common
voltage. Further, when the high voltage PWM circuit is the full
bridge converter, the wireless charging circuit further includes a
detection switch. The control terminal of the detection switch is
coupled to the control circuit, the first terminal of the detection
switch is coupled to the second input terminal of the resonant
circuit, and the second terminal of the detection switch is coupled
to the common voltage. When the wireless charging circuit
determines whether an external object is disposed on the wireless
power converter or not, the control circuit controls to connect the
first terminal of the detection switch and the second terminal of
the detection switch.
[0013] The present invention further provides a mobile power bank.
The mobile power bank includes a battery and a wireless charging
circuit. The wireless charging circuit includes a boost DC to DC
converter, a unidirectional conductive element and a wireless power
converter. The boost DC to DC converter includes an input terminal
and an output terminal, wherein the input terminal of the boost DC
to DC converter is coupled to the battery to receive a battery
voltage, wherein the output terminal of the boost DC to DC
converter is for outputting a converted DC voltage. The
unidirectional conductive element includes a first terminal and a
second terminal, wherein the first terminal of the unidirectional
conductive element is coupled to the battery to receive the battery
voltage, wherein a current direction is from the first terminal of
the unidirectional conductive element to the second terminal of the
unidirectional conductive element. The wireless power converter is
coupled to the second terminal of the unidirectional conductive
element and the output terminal of the boost DC to DC
converter.
[0014] When the wireless charging circuit determines whether an
external object is disposed on the wireless power converter or not,
the wireless power converter disables the boost DC to DC converter.
When the wireless charging circuit determines that an external
object is disposed on the wireless power converter, the wireless
power converter enables the boost DC to DC converter.
[0015] The spirit of the present invention is to disable the DC to
DC converter when the wireless charging circuit determines whether
an external object is disposed on the wireless power converter or
not. Instead, when the wireless charging circuit determines whether
an external object is disposed on the wireless power converter or
not, the battery voltage is supplied to the wireless charging
circuit without conversion to perform the detection of external
object. When the wireless charging circuit determines that an
external object is disposed on the wireless power converter, the
wireless power converter enables the boost DC to DC converter.
Thus, when the detection of an external object is performed, there
is no extra power consumption from the DC to DC converter.
Meanwhile, the power consumption of the detection of an external
wireless power receiver can be also reduced.
[0016] Further scope of the applicability of the present invention
will become apparent from the detailed description given
hereinafter. However, it should be understood that the detailed
description and specific examples, while indicating preferred
embodiments of the invention, are given by way of illustration
only, since various changes and modifications within the spirit and
scope of the invention will become apparent to those skilled in the
art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The present invention will become more fully understood from
the detailed description given hereinbelow and the accompanying
drawings which are given by way of illustration only, and thus are
not limitative of the present invention.
[0018] FIG. 1 illustrates a circuit diagram depicting a wireless
charging circuit according to a conventional art.
[0019] FIG. 2 illustrates a circuit diagram depicting a mobile
power bank according to a preferred embodiment of the present
invention.
[0020] FIG. 3 illustrates a circuit diagram depicting a mobile
power bank according to a preferred embodiment of the present
invention.
[0021] FIG. 4 illustrates a circuit diagram depicting a mobile
power bank according to a preferred embodiment of the present
invention.
[0022] FIG. 5 illustrates a circuit diagram depicting a mobile
power bank according to a preferred embodiment of the present
invention.
[0023] FIG. 6 illustrates a circuit diagram depicting a mobile
power bank according to a preferred embodiment of the present
invention.
[0024] FIG. 7 illustrates a circuit diagram depicting a mobile
power bank according to a preferred embodiment of the present
invention.
[0025] FIG. 8 illustrates a circuit diagram depicting a mobile
power bank according to a preferred embodiment of the present
invention.
[0026] FIG. 9 illustrates a circuit diagram depicting a mobile
power bank according to a preferred embodiment of the present
invention.
[0027] FIG. 10 illustrates a circuit diagram depicting a mobile
power bank according to a preferred embodiment of the present
invention.
[0028] FIG. 11 illustrates a circuit diagram depicting a mobile
power bank according to a preferred embodiment of the present
invention.
[0029] FIG. 12A illustrates a circuit diagram depicting a current
detection circuit according to a preferred embodiment of the
present invention.
[0030] FIG. 12B illustrates a circuit diagram depicting a current
detection circuit according to a preferred embodiment of the
present invention.
[0031] FIG. 12C illustrates a circuit diagram depicting a current
detection circuit according to a preferred embodiment of the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0032] The present invention will be apparent from the following
detailed description, which proceeds with reference to the
accompanying drawings, wherein the same references relate to the
same elements.
[0033] FIG. 2 illustrates a circuit diagram depicting a mobile
power bank according to a preferred embodiment of the present
invention. Referring to FIG. 2, the mobile power bank includes a
battery 201, a unidirectional conductive element 202 and a wireless
charging circuit 203 of the present embodiment of the present
invention. The wireless charging circuit 203 includes a boost DC to
DC converter 204, a control circuit 205 and a wireless power
converter 206. The boost DC to DC converter 204 is used for
converting 3.7V supplied from the battery 201 to 5V which is
required by the wireless power converter 206. The wireless power
converter 206 includes a half bridge converter 207, a resonant
circuit 208 and a driving circuit 209. The half bridge converter
207 includes a upper switch M1 and a lower switch M2.
[0034] The operation of the control circuit 205 depends on the 3.7V
supplied by the battery 201. The operation of the driving circuit
209 depends on the 5V outputted from by the boost DC to DC
converter 204. In addition, the control circuit 205 is used for
controlling whether the boost DC to DC converter 204 is enabled or
not. Moreover, although the resonant circuit 208 is implemented by
a resonant coil L21 and a resonant capacitor C21, people having
ordinary skill in the art should know that the number of the
resonant coil L21 and the resonant capacitor C21 can be changed
according to different design, and the coupling relationship of the
resonant coil L21 and the resonant capacitor C21 can be changed,
such as interchanging the resonant coil L21 with the resonant
capacitor C21. Thus, the present invention is not limited
thereto.
[0035] When the wireless charging circuit 203 begins to detect a
wireless power receiver (or an external object), the boost DC to DC
converter 204 and the driving circuit 209 is disabled. Instead, the
control circuit 205 directly outputs the control signals G1 and G2
to control the gates of the switch elements M1 and M2 of the half
bridge converter 207 to output a low voltage pulse width modulation
(PWM) signal, whose amplitude is about 3.7V, to the resonant
circuit 208. Then, the control circuit 205 begins to detect the
current of the resonant circuit 208. Generally, the control circuit
205 would detect the voltage Vsense from the current sensing
resistor R21 to serve as the means for detecting the current of the
resonant circuit 208. When the current flowing through the current
sensing resistor R21 is increased, it represent that there is an
object being disposed on the resonant coil L21. At this time, the
control circuit 205 enables the boost DC to DC converter 204, and
controls the driving circuit 209 to drive the half bridge converter
with 5V to output a high voltage PWM signal whose amplitude is
about 5V, to attempt establishing a wireless connection with the
object.
[0036] Further, in order to prevent the 5V outputted from the boost
DC to DC converter 204 returning to the battery 201, in the
abovementioned embodiment, the unidirectional conductive element
202 is coupled between the battery 201 and the output terminal of
the boost DC to DC converter 204. Thus, the 5V outputted from the
boost DC to DC converter 204 would not feed back to the battery
201. In the abovementioned embodiment, since the amplitude of the
control signal outputted from the control circuit 205 is about
3.7V, the control signal is insufficient to drive the gate of the
upper switch M1 if the boost DC to DC converter 204 is enabled.
Thus, the driving circuit 209 is with a function of level shift for
converting the 3.7V amplitude of the driving signal to the 5V
amplitude of the driving signal. In addition, the terminals of the
control circuit 205 and the terminals of the driving circuit 209
are coupled to the half bridge converter 207. In order to prevent
the driving signal outputted from the driving circuit 209 to
interfere the operation of the control circuit 205, a resistor or a
diode can be selectively coupled between the control circuit 205
and the gates of the switching elements M1 and M2 of the half
bridge converter 207.
[0037] Moreover, although the unidirectional conductive element 202
in this embodiment is implemented by a diode, people having
ordinary skill in the art should know that the unidirectional
conductive element 202 also can be implemented by a electrical
switch or a diode-connected transistor. Thus, the present invention
is not limited thereto.
[0038] FIG. 3 illustrates a circuit diagram depicting a mobile
power bank according to a preferred embodiment of the present
invention. Referring to FIG. 2 and FIG. 3, in this embodiment, the
wireless charging circuit 203 includes the boost DC to DC converter
204, a control circuit 205 and the wireless power converter 206.
The wireless power converter 206 includes a first half bridge
converter 301, the resonant circuit 208, the driving circuit 209
and a second half bridge converter 302. The first half bridge
converter 301 includes a upper switch M1 and a lower switch M2. The
second half bridge converter 302 includes an upper switch M3 and a
lower switch M4.
[0039] Similarly, the operation of the control circuit 205 depends
on the 3.7V supplied by the battery 201. The operation of the
driving circuit 209 depends on the 5V outputted from by the boost
DC to DC converter 204. In addition, the control circuit 205 is
used for controlling whether the boost DC to DC converter 204 is
enabled or not. Moreover, although the resonant circuit 208 is
implemented by a resonant coil L21 and a resonant capacitor C21,
people having ordinary skill in the art should know that the number
of the resonant coil L21 and the resonant capacitor C21 can be
changed according to different design, and the coupling
relationship of the resonant coil L21 and the resonant capacitor
C21 can be changed, such as interchanging the resonant coil L21
with the resonant capacitor C21. Thus, the present invention is not
limited thereto.
[0040] In this embodiment, a low voltage pulse width modulation
circuit, which is the half bridge converter 301, is used to replace
the unidirectional conductive element 202. When the wireless
charging circuit 203 begins to detect the wireless power receiver
(or an external object), the boost DC to DC converter 204, the
driving circuit 209 and the second half bridge converter 302 are
disabled. Instead, the control circuit 205 controls the first half
bridge converter 301 to output a low voltage PWM signal, whose
amplitude is about 3.7V, to the resonant circuit 208. The control
circuit then starts to detect the current flowing through the
resonant circuit 208. Generally, the control circuit 205 would
detect the voltage Vsense from the current sensing resistor R21 to
serve as the means for detecting the current of the resonant
circuit 208. When the current flowing through the current sensing
resistor R21 is increased, it represent that there is an object
being disposed on the resonant coil L21. At this time, the control
circuit 205 enables the boost DC to DC converter 204, and controls
the driving circuit 209 to drive the half bridge converter with 5V
to output a high voltage PWM signal whose amplitude is about 5V, to
attempt establishing the connection with the object.
[0041] According to the abovementioned embodiment, people having
ordinary skill in the art should know that the boost DC to DC
converter 204 is disabled during the wireless charging circuit
detecting an external object. Thus, the energy waste causing by the
efficiency of the boost DC to DC converter 204 can be saved.
Beside, when the boost DC to DC converter 204 starts to operate,
since the upper switch M1 of the first half bridge converter 301 is
coupled to the battery voltage and the upper switch M3 of the
second half bridge converter 302 is coupled to 5V outputted from
the boost DC to DC converter 204, the operation of the first half
bridge converter 301 and the operation of the second half bridge
converter 302 would not interfere each others. Also, the 5V
outputted from the boost DC to DC converter 204 will not feed back
to the battery 201.
[0042] FIG. 4 illustrates a circuit diagram depicting a mobile
power bank according to a preferred embodiment of the present
invention. Referring to FIG. 3 and FIG. 4, the difference between
the circuit in FIG. 4 and the circuit in FIG. 3 is that the
unidirectional conductive element 401 is coupled between the upper
switch M1 of the first half bridge converter 301 and the battery
201. FIG. 5 illustrates a circuit diagram depicting a mobile power
bank according to a preferred embodiment of the present invention.
Referring to FIG. 3 and FIG. 5, the difference between the circuit
in FIG. 5 and the circuit in FIG. 3 is that the unidirectional
conductive element 501 is coupled between the upper switch M1 of
the first half bridge converter 301 and the upper switch M3 of the
second half bridge converter 302. The unidirectional conductive
element 501 would block the output voltage Vo outputted from the
boost DC to DC converter 204 to feed back to the battery 201.
[0043] FIG. 6 illustrates a circuit diagram depicting a mobile
power bank according to a preferred embodiment of the present
invention. Referring to FIG. 3 and FIG. 6, the difference between
the circuit in FIG. 6 and the circuit in FIG. 3 is that the control
circuit 205 samples the voltage of the node N60 coupled to the
resonant coil L21 and the resonant capacitor C21 instead of the
voltage Vsense of the current sensing resistor R21.
[0044] FIG. 7 illustrates a circuit diagram depicting a mobile
power bank according to a preferred embodiment of the present
invention. Referring to FIG. 6 and FIG. 7, the difference between
the circuit in FIG. 7 and the circuit in FIG. 6 is that the
unidirectional conductive element 701 is coupled between the node
N70 and the node N71. Since the current of the unidirectional
conductive element 701 only can flow from the battery 201 to the
second half bridge 302, the output voltage Vo of the boost DC to DC
converter 204 would not affect the battery 201.
[0045] FIG. 8 illustrates a circuit diagram depicting a mobile
power bank according to a preferred embodiment of the present
invention. Referring to FIG. 3 and FIG. 8, the difference between
the circuit in FIG. 8 and the circuit in FIG. 3 is that the second
half bridge converter 302 is replaced by the full bridge converter
801. The full bridge converter 801 includes a first upper switch
M5, a first lower switch M6, a second upper switch M7 and a second
lower switch M8. Thus, the control circuit 205 must output six gate
control signals G1, G2, G3' .about.G6'. And the driving circuit 209
must output four gate control signals G3.about.G6 to respectively
drive the first upper switch M5, the first lower switch M6, the
second upper switch M7 and the second lower switch M8. The
operation concept of the circuit in FIG. 8 is essentially the same
as the operation concept of the circuit in FIG. 3. The detail
description is omitted.
[0046] FIG. 9 illustrates a circuit diagram depicting a mobile
power bank according to a preferred embodiment of the present
invention. Referring to FIG. 8 and FIG. 9, the difference between
the circuit in FIG. 9 and the circuit in FIG. 8 is that the circuit
in FIG. 9 has extra unidirectional conductive element 901. Since
the current of the unidirectional conductive element 901 only can
flow from the battery 201 to the full bridge converter 801, the
output voltage Vo of the boost DC to DC converter 204 would not
affect the battery 201.
[0047] FIG. 10 illustrates a circuit diagram depicting a mobile
power bank according to a preferred embodiment of the present
invention. Referring to FIG. 8 and FIG. 10, the difference between
the circuit in FIG. 9 and the circuit in FIG. 8 is that the circuit
in FIG. 10 has an extra switch M9. And the control circuit also has
an extra control terminal G7 coupled to the gate of the switch M9.
Similarly, when the wireless charging circuit 203 in this
embodiment begins to detect the wireless power receiver (or an
external object), the boost DC to DC converter 204 and the driving
circuit 209 are disabled. Instead, the control circuit 205 output
the control signals G1 and G2 to control the gates of the switch M1
and M2 of the first half bridge converter 301 to output the low
voltage PWM signal, whose amplitude is about 3.7V, to the resonant
circuit 208. Meanwhile, the control circuit 205 controls the gate
G7 of the switch M9 to turn switch M9 on such that the resonant
circuit 208 is grounded.
[0048] Next, the control circuit then starts to detect the current
flowing through the resonant circuit 208. Generally, the control
circuit 205 would detect the voltage Vsense from the current
sensing resistor R21 to serve as the means for detecting the
current of the resonant circuit 208. When the current flowing
through the current sensing resistor R21 is increased, it represent
that there is an object being disposed on the resonant coil L21. At
this time, the control circuit 205 enables the boost DC to DC
converter 204. Meanwhile, the control circuit 205 controls the gate
G7 of the switch M9 to turn the switch M9 off. Further, the control
circuit 205 then controls the driving circuit 209 to drive the four
switch M5, M6, M7 and M8 of the full bridge converter 801 to output
a high voltage PWM signal to the resonant circuit to attempt
establishing the connection with the object, wherein the amplitude
of the high voltage PWM signal is about 5V.
[0049] Moreover, in order to prevent the 5V outputted from the
boost DC to DC converter 204 returning to the battery 201, in the
abovementioned embodiment, there is no electrical connection
between the output terminal of the boost DC to DC converter 204 and
the first half bridge converter 301. Thus, the 5V outputted from
the boost DC to DC converter 204 would not feed back to the battery
201. In the abovementioned embodiment, since the amplitude of the
control signal outputted from the control circuit 205 is about
3.7V, the control signals are insufficient to drive the switches
M5, M6, M7 and M8 of the full bridge converter 801. Thus, the
driving circuit 209 is with a function of level shift for
converting the 3.7V amplitude of the driving signal to the 5V
amplitude of the driving signal.
[0050] FIG. 11 illustrates a circuit diagram depicting a mobile
power bank according to a preferred embodiment of the present
invention. Referring to FIG. 10 and FIG. 11, the difference between
the circuit in FIG. 11 and the circuit in FIG. 10 is that the
resistor R21 is removed. The control circuit 205 samples the
voltage Vr of the node N11 of the resonant circuit 208 to serve as
the means for detecting the current of the resonant circuit 208.
The node voltage Vr of the node N11 is proportional to the current
flowing through the resonant circuit 208. Thus, the control circuit
205 can obtain the current flowing through the resonant circuit 208
by detecting the voltage Vr of the node N11.
[0051] FIG. 12A illustrates a circuit diagram depicting a current
detection circuit according to a preferred embodiment of the
present invention. FIG. 12B illustrates a circuit diagram depicting
a current detection circuit according to a preferred embodiment of
the present invention. FIG. 12C illustrates a circuit diagram
depicting a current detection circuit according to a preferred
embodiment of the present invention. Referring to FIG. 12A, the
current detection circuit can be coupled between the control
circuit 205 and the node N11 of the resonant circuit 208 in FIG. 11
or be coupled between the control circuit 205 and the node N60 in
FIG. 6. The current detection circuit may also be coupled between
the current sensing resistor R21 and the control circuit 205.
Assuming the current detection circuit is applied to the circuit in
FIG. 11, the resistor R121 is coupled between the node N11 of the
resonant circuit and the capacitor C121. The resistors R122 and
R123 are used for dividing the voltage of another terminal of the
capacitor C121. Afterward, the divided voltage is sampled by the
quasi-peak detector implemented by the diode D121, the capacitor
C122 and the resistor R124. The control circuit 205 detects the DC
voltage VDC to determine the magnitude of the current flowing
through the resonant circuit 208.
[0052] Similarly, referring to FIG. 12B, assuming the current
detection circuit is applied to the circuit in FIG. 11, the diode
D122 is coupled between the node N11 of the resonant circuit 208
and the resistor R125. The resistors R125 and R126 are used for
dividing the voltage of the cathode D122 and then outputting the
divided voltage to the capacitor C123. The control circuit 205
detects the DC voltage VDC to determine the magnitude of the
current flowing through the resonant circuit 208. Analogously,
referring to FIG. 12C, assuming the current detection circuit is
applied to the circuit in FIG. 11, the resistor R127 is coupled
between the node N11 of the resonant circuit 208 and the diode
D123. The resistors R128 and R129 are used for dividing the voltage
of the cathode of the diode D123 to output the divided voltage to
the capacitor C124. The control circuit 205 detects the DC voltage
VDC to determine the magnitude of the current flowing through the
resonant circuit 208.
[0053] In summary, the spirit of the present invention is to
disable the DC to DC converter while the wireless charging circuit
determines whether an external object is disposed on the wireless
power converter or not. Instead, when the wireless charging circuit
determines whether an external object is disposed on the wireless
power converter or not, the battery voltage is supplied to the
wireless charging circuit without conversion to perform the
detection of external object. When the wireless charging circuit
determines that an external object is disposed on the wireless
power converter, the wireless power converter enables the boost DC
to DC converter. Thus, when the detection of an external object is
performed, there is no extra power consumption from the DC to DC
converter. Meanwhile, the power consumption of the detection of an
external wireless power receiver can be also reduced.
[0054] While the invention has been described by way of examples
and in terms of preferred embodiments, it is to be understood that
the invention is not limited thereto. To the contrary, it is
intended to cover various modifications. Therefore, the scope of
the appended claims should be accorded the broadest interpretation
so as to encompass all such modifications.
* * * * *